ATLASGAL

ATLASGAL
ESO/H.H.Heyer · CC BY 4.0 · source
Name	ATLASGAL
Caption	APEX telescope at Llano de Chajnantor Observing Site
Organization	European Southern Observatory
Location	Llano de Chajnantor
Wavelength	870 μm
Began	2007
Status	Completed

ATLASGAL The APEX Telescope Large Area Survey of the Galaxy was a submillimetre continuum survey that mapped the inner Galactic plane at 870 μm. It provided a uniform, sensitive dataset used by researchers across projects associated with European Southern Observatory, Max Planck Institute for Radio Astronomy, Leiden Observatory, Institut de Radioastronomie Millimétrique, and University of Chile. The survey complemented observations from facilities such as Herschel Space Observatory, Spitzer Space Telescope, Planck (spacecraft), Very Large Array, and ALMA.

Overview

ATLASGAL targeted the inner Milky Way, focusing on regions near Galactic Center and the Scutum–Centaurus Arm to inventory cold, dense structures linked to star formation. The survey bridged scales between large-area mapping by Planck (spacecraft) and high-resolution imaging by ALMA and SMA (observatory), enabling cross-comparison with data from Herschel Space Observatory Open Time programs, Spitzer Space Telescope Legacy surveys like GLIMPSE, and radio continuum surveys from VLA projects. Key collaborating institutions included European Southern Observatory, Onsala Space Observatory, Max Planck Society, and national observatories in Chile and Germany.

Observations and Instrumentation

Observations were conducted with the 12-m Atacama Pathfinder Experiment telescope on the Chajnantor Plateau near San Pedro de Atacama, exploiting the high, dry site shared by projects such as ALMA and APEX-SZ. The survey used the LABOCA bolometer camera, developed by teams at Max Planck Institute for Radio Astronomy, University of Cologne, and partners including MPIfR and European Southern Observatory. LABOCA provided a beam of ~19″ at 870 μm, comparable to instruments like SCUBA on the James Clerk Maxwell Telescope and later complemented by heterodyne instruments at IRAM 30m. Observing campaigns were scheduled to coordinate with seasonal windows used by Atacama Large Millimeter Array and atmospheric monitoring programs run by NOEMA collaborators.

Survey Design and Data Processing

ATLASGAL covered Galactic longitudes and latitudes defined to capture spiral-arm complexes such as Perseus Arm and Sagittarius Arm and massive star-forming regions including W43, W49, and W51. The observing strategy balanced uniform sensitivity with mosaicing procedures employed in surveys like Hi-GAL from Herschel Space Observatory and radio surveys like CORNISH. Raw bolometer timestreams were processed with pipelines developed by groups at Leiden Observatory and Max Planck Institute for Astronomy, using methods analogous to techniques from SCUBA-2 and Bolocam reductions. Data calibration referenced planets and secondary calibrators used by IRAM and JCMT teams, and spatial filtering effects were characterized following approaches from Planck Collaboration analyses.

Scientific Results

ATLASGAL produced catalogues of cold clumps and dense cores that informed studies of high-mass star formation, clump mass functions, and filamentary structure, working in concert with surveys like BGPS and Hi-GAL. Results illuminated the lifecycle from infrared-dark clouds identified in GLIMPSE maps to hot molecular cores traced by MALT90 and maser surveys such as those by Methanol Multibeam Survey. Studies combining ATLASGAL with spectroscopic programs at IRAM 30m, APEX heterodyne receivers, and Mopra Radio Telescope revealed velocity structure in complexes like G327.3-0.6 and chemical differentiation linked to feedback processes studied in Orion Nebula and W49A. ATLASGAL data were pivotal for investigations into initial conditions of cluster formation, comparisons with theoretical models by groups at Harvard University, Max Planck Institute for Astrophysics, and Princeton University, and for planning follow-up high-resolution imaging with ALMA and VLA.

Data Access and Catalogues

Processed maps and compact source catalogues were released through archives maintained by European Southern Observatory and partner institutions including CDS (Strasbourg), SIMBAD, and the NASA/IPAC Infrared Science Archive for cross-matching. Catalogues were cross-referenced with surveys such as RMS survey, ATLAS, BGPS, and GLIMPSE to provide multiwavelength counterparts. Teams at Leiden Observatory, Max Planck Institute for Radio Astronomy, and University of Vienna produced value-added products, and tools used for access and analysis included software from CASA, HIPE, and community packages developed at Astropy and APLpy groups.

Legacy and Impact

ATLASGAL remains a legacy dataset underpinning projects on Galactic structure, massive star formation, and filamentary interstellar medium studies pursued by institutions like European Space Agency, Max Planck Society, National Radio Astronomy Observatory, and research groups at University of Cambridge, University of Oxford, University of Tokyo, and Peking University. Its maps continue to guide ALMA proposals, infrared follow-ups with SOFIA and James Webb Space Telescope programs, and synergy with future surveys by SKA pathfinders and millimetre facilities such as NOEMA. The survey fostered collaborations across observatories including ESO, IRAM, MPIfR, and universities worldwide, influencing graduate training and cross-disciplinary initiatives in observational astrophysics.

Category:Submillimetre astronomy Category:Galactic surveys Category:Atacama Pathfinder Experiment